Safety knife



June 28, 1949.

A. c. WOLF SAFETY KNIFE Filed March "r, 1946' Inventor w r/ha 2 w m W VC3 n M .w. M w m Patented June 28, 1949 UNITED STATES PT NT OFFICE SAFETYKNIFE Application March 7, 1946, Serial No. 652,591

3 Claims.

This invention relates to new and useful improvements and structuralrefinements in safety knives, the principal object of the inventionbeing to provide a device of the character herein described, which isparticularly adapted for use by workers in textile industries, paper orrubber mills, shoe factories, and similar other occupations.

A further object of the invention is to provide a device which is of apocket knife nature, consisting generally of a projectible andretractible blade slidably positioned in an enclosing sheath, The bladeis projectible into the cutting position by manipulating a suitablypositioned push-button and the novelty of the invention resides chieflyin the combination of the foregoing with automatic means for retractingthe blade into the sheath, as soon as the push-button is released.

The safety factor of the invention thus becomes readily apparent and afurther object of the invention is to provide a device which is ofsimple construction and which cannot easily become damaged.

Another object of the invention is to provide a knife of the characterdescribed, which may be opened and manipulated with one hand, while thework is being held with the other.

An additional object of the invention is to provide a knife which, inaddition to its specific uses as above outlined, may also be employed inplace of conventional knives for cutting or slicing operations ingeneral.

With the above more important objects in view, and such other objects asmay become apparent as this specification proceeds, the inventionconsists essentially of the arrangement and construction of parts asillustrated in the accompanying drawings, in which- Figure 1 is a sideelevation of the invention, showing the blade thereof in the opened orprojected position.

Figure 2 is a plan view of the same, but showing the blade retracted.

Figure 3 is a longitudinal cross-sectional view of the subject shown inFigure 1 (blade projected) Figure 4 is a similar cross-sectional view,but with the blade retracted.

Figure 5 is a cross-sectional view, taken in the plane of the line 55 inFigure 4, and

Figure 6 is a cross-sectional view, taken in the plane of the line 6-6in Figure 4.

Like characters of reference are used to designate like parts in thespecification and throughout the several views.

Referring now to the accompanying drawings in detail, the inventionconsists of an elongated 2 sheath, configurated substantially as shownand designated by the general reference character [0. A suitable bladeH, provided with the cutting edges i2 is slidably positioned in thesheath, being projectible and retractible through an opening 23 providedin one end of the same.

A push-button I4 is formed integrally with a shank l5, whereby it issecured in a suitable aperture provided adjacent the inner end of theblade ll. One side of the sheath [0 is formed with a longitudinallyextending slot l6 and the shank l5 slidably engages this slot, as willbe clearly apparent from the accompanying drawings. The button M may besuitably knurled and it will be noted that by sliding the button in theslot, the blade II will be projected from or retracted into the sheathI0.

A tension spring I1 is positioned in the sheath, the blade I I beingprovided for this purpose with an eye [8 to which one end of the springmay be anchored. The remaining end of the spring is secured to a furthereye 19, this being mounted adjacent the inner closed end of the sheathH].

The cross-section of the sheath I0 is best illustrated in theaccompanying Figures 5 and 6, this being such as to accommodate theblade and the aforementioned spring, as will be clearly understoodwithout further description.

When the invention is placed in use, the blade I I is projected into itsworking position by simply pushing the button M in the direction of thearrow 20. During this operation, the spring ll will be stretched asshown in Figure 3, this figure, together with Figure 1, illustrating theprojected position of the blade.

As soon as the button It is released, the resiliency of the spring I!will automatically retract the blade I! to its closed or concealedposition in the sheath, as is illustrated in Figure 4. It will be notedthat while in this position, the entire blade is covered by the sheathand accidental or unintentional contact with the cutting edges of thesame is thereby completely eliminated,

It is presumed that the sliding action of the shank E5 in the slot 16will be sufiicient to prevent dipping of the inner end of the blade intothe chamber occupied by the spring ll. However, if this is notconsidered suflicient, the movement of the blade may be further guidedby means of a transversely extending pin 2|, protruding at both sides ofthe blade II. The inner side walls of the sheath l0 are formed with apair of longitudinally extending recesses 22, the protruding ends of thepin 2| slidably engaging these recesses, and thus guiding the slidingmovement of the blade.

It should be understood that the provision on the pin 2| and therecesses 22 may be added if the guiding action of the shank I5 in theslot I6 is considered insuflicient.

It is believed that the operation and use of the invention will beclearly understood from the foregoing and further description thereof isaccordingly considered unnecessary.

While in the foregoing there has been shown and described the preferredembodiment of this invention it is to be understood that minor changesin the details of construction, combination and arrangement of parts maybe resorted; to without departing from the spirit and scope of theinvention as claimed.

What I claim as my invention is:

1. A safety knife comprising in combination,

a sheath formed with an opening in one end thereof, a slidable blade insaid sheath, said blade being projectible and retractible through saidopening, a push-button on said blade, said sheath having in one sidethereof a longitudinally extending slot, said button slidably engagingsaid slot and protruding therethrough, a coiled tension spring in saidsheath and d'isposed on one side of the blade,v an eye on said blade anda further eye in the closed end of said sheath, said spring extendingbetween said eyes and normally urging said blade. into the retractedposition, and means to prevent the blade from entering the spaceoccupied by said spring.

2. The device as defined in claim 1 together with a pin extendingtransversely through said blade and projecting at both sides therefrom,the inner side Walls of said sheath being formed with a pair oflongitudinally extending recesses, and the projecting ends of said pinslidably engaging said recesses for guiding the movement of said blade,the spring *being housed in a hollow portion of said sheath extendinglongitudinally thereof and on one side of the blade when said blade isin retracted position.

3. A device according to claim 2 and in which said knife is bevelled atthe outer end, and said sheath has an' inwardly projecting slide bearingmember disposed adjacent said opening in said sheath and at one side ofthe blade, said member substantially closing the outer end of the spacewithin the sheath occupied by said spring.

ALLEN C. WOLF.

REFERENCES CITED The following references are of record in the the ofthis patent:

UNITED STATES PATENTS Number Name Date 2,237,331 Bodkin et al Apr. 8,1941 FOREIGN PATENTS Number Country Date 102,546 Germany Apr. 26, 1899

